The purpose of this proposal is to investigate the role of REM sleep/dreaming in mood regulation in men and women, specifically to discover the contribution of this psychophysiological state to the increased vulnerability of women to mood disorder. Three studies are proposed: The first 60 normal students will be recorded for two nights to test that: l) that there is a significant mood change from night to morning, 2) that women have less sleep-related mood change than men, 3) that presleep negative mood correlates to REM sleep measures, 4) that mood change is related to within dream and between dream affect reversals, 5) females will show fewer affect dream reversals than males. The second study will develop computer software to compare affect reversals in dreams of male and female depressed and not depressed subjects collected under previous funding. The third will test a new sample of 32 depressed males and females over an eight month period to collect weekly waking mood ratings pre and postsleep and monthly sleep and dream data to follow the course of waking mood stability or change in the two sexes on a longitudinal basis and its relation to REM sleep/dreaming variables.